1. Field of the Invention
The present invention relates to a golf club. In particular, the present invention relates to a golf club in which a head and a shaft are detachably mounted to each other.
2. Description of the Related Art
A golf club in which a head and a shaft are detachably mounted to each other has been proposed. Easiness in detachably mounting the shaft to the head body is useful for several reasons. If golf players themselves detachably mount the shaft to the head easily, the golf players can change the head and the shaft easily. For example, golf players who cannot satisfy the performance of the purchased golf club easily change the head and the shaft by themselves. The golf players themselves can easily assemble an original golf club in which a favorite head and a favorite shaft are combined. The golf players can purchase the favorite head and the favorite shaft, and can assemble the head and the shaft by themselves. Stores which sell the golf clubs can select the combination of the head and the shaft properly corresponding the golf player, and sell the combination. The head and the shaft detachably mounted easily facilitate the custom-made golf club.
Japanese Patent Application National Publication (Laid-Open) No. 2008-520274 (US 2006/105855), Japanese Patent Application National Publication (Laid-Open) No. 2005-533626 (WO2004/009186), and Japanese Patent Application Laid-Open No. 2006-42951 disclose structures where a head and a shaft are easily mounted and detached.
Furthermore, Japanese Patent Application Laid-Open Nos. 2000-5349 and 2005-270402, and WO2009/009291 (PCT application) disclose a golf club having an angle θ1 between a shaft axis and a hosel axis in a mounting/detaching mechanism of a head and a shaft. In these inventions, a loft angle, a lie angle, and a hook angle (face angle) can be adjusted by a circumferential position of the shaft.
On the other hand, a shaft having a property producing coupled deformations of bending and torsion has been proposed. The property is also referred to as “anisotropy” in the present application. The shaft having the anisotropy is also referred to as an “anisotropic shaft”. The shafts having the anisotropy are disclosed in Japanese Patent Application Laid-Open Nos. 3-227616 (U.S. Pat. No. 5,348,777, U.S. Pat. No. 5,242,721), 11-76480, 11-299944 (U.S. Pat. No. 6,773,358), and 2003-265661. These anisotropic shafts can correct hook and slice.